It purportedly runs at about 80 percent of the performance of the host CPU, according to the developer.

"Now about 600m PC users can have the Mac advantage," says the software's developer, Arben Kryeziu. "One computer to use all software and if PC users would use Mac software to get email, perhaps they would avoid viruses, Trojans and spyware."

Cherry OS is being distributed as an online download, and costs $49.95 (£28).

Mac operating system software and application software is not included.